Are "cup" and "glass" the same in English? Can I call a "glass" a cup made of plastic?

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    A dictionary definition for cup reads: A concave vessel for drinking from, usually made of opaque material (as opposed to a glass). The equivalent for glass reads: A vessel from which one drinks, especially one made of glass, plastic, or similar translucent or semi-translucent material. Jul 24 '12 at 13:30
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    I know this isn't the technical definition, but when I hear "cup" I think of a short cylindrical container with a handle, as in a coffee cup or a tea cup. When I hear "glass" I think of a taller, more conical container without a handle, as in a glass of water or a glass of beer.
    – Kevin
    Jul 24 '12 at 15:04
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    Isn't a glass made out of glass? And a cup is not?
    – Mitch
    Jul 24 '12 at 15:55
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    It’s interesting that there is disagreement over this. To my (New England) mind, a glass is always unequivocally made of glass, and a cup is more generally anything cup-shaped—you could have a glass cup, for instance. And a drinking container with a handle is a cup if it isn’t a mug.
    – Jon Purdy
    Jul 24 '12 at 16:18
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    I think this is a case where a general reference question nevertheless has an interesting answer that is not covered very well by most reference sources: when does shape take precedence (so that a plastic glass-shaped drinking vessel is just a "glass") and when does material take precedence (so that if it's made of plastic, it can only ever be a "cup", even if its shape is identical to a glass)?
    – Marthaª
    Jul 24 '12 at 16:45

The shapes are variable, but the meanings converge on Prototypes.

In a classic set of experiments in 1973, Labov showed how this works with cup and mug.

Labov, William. 1973. 'The Boundaries of Words and Their Meanings' in R. Fasold (ed), Variation in the Form and Use of Language: A Sociolinguistics Reader. Georgetown University Press, 1983.

To summarize the relevant points, no, cup and glass are not the same in English. Yes, you can call a cup made of plastic a glass, depending on the context.

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    Fascinating. But for those of us how have just a little more time, could you expand on that a little? ;-) By the way, I had a look at your archive of alt.usage.english postings. Learnt a lot. Thanks!
    – Pitarou
    Jul 25 '12 at 5:01

To me, a cup is a general term. Mugs are a type of cup with thick sides and a often a handle. I would call beer steins or coffee mugs specializations of this type. A glass is a type of cup, usually glass, often with thinner sides and usually no handle, but it may or may not have a stem. A tumbler doesn't have a stem. A wine glass does. I guess a paper cup might be considered a tumbler, but it's not a glass.

Bottles, jugs, and thermoses are containers for drinks but not cups.


The crucial, and rather obvious, difference is that a cup is normally made of earthenware or porcelain and a glass is made of, well, glass.

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    That is certainly the etymology of the words, but today, if short and has a handle, it's a cup; if it's tall or lacks a handle, it's a glass, regardless of construction. Jul 24 '12 at 15:19
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    @Malvolio: Not, at least in the case of a glass, where I live. Jul 24 '12 at 15:32
  • well, where do you live? (Barrie Olde England? Sorry...) Jul 24 '12 at 15:33
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    @Marthaª: You were clearly never a boy scout or in the British army. Jul 24 '12 at 17:50
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    @Barrie: Yes -- a metal mug, white enamel with a blue rim and handle. I remember. At least, I remember my father's.
    – Andrew Leach
    Jul 24 '12 at 18:00

No a cup and a glass are different shapes.

Even a copy of a glass, the same shape and size, made of plastic is called a glass. So if you buy beer but want to take it outside to drink in the beer-garden you normally have to have it in a plastic glass

cite: Pubs warn over plastic pints plan

  • 2
    I don't agree. Unless it's made of glass or something very similar to glass that shatters, I'd be inclined to call it a cup or beaker.
    – Jez
    Jul 24 '12 at 14:53
  • I don't think you would be understood if you went into a pub and asked for a beaker of beer.
    – mgb
    Jul 24 '12 at 14:57
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    No, but we don't ask for a glass of beer here either - we ask for a pint or something.
    – Jez
    Jul 24 '12 at 15:12
  • I'd call a clear (or colored but transparent) plastic cup a glass, particularly if it is made from thick plastic.
    – Kit Z. Fox
    Jul 24 '12 at 19:11
  • Yes, but why a plastic cup is called like that, and very rarely a plastic glass?
    – Quidam
    Dec 7 '19 at 17:27

The difference is that a cup is stouter and a glass is narrower. You might say that the cup more closely approximates a cube, but the glass a (tall) cylinder.

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    Not always the case, a pint glass is very stout and looks a bit like a cube.
    – Mari-Lou A
    Feb 23 '14 at 10:51
  • Why a plastic cup?
    – Quidam
    Dec 7 '19 at 17:27

Cups and mugs have handles. Glasses, regardless of what they are made of, do not.

  • 1
    What about traditional beer glasses? They have handles.
    – Mari-Lou A
    Feb 23 '14 at 10:37
  • @Mari-LouA, to add to the confusion, these vessels are in fact jugs. Feb 23 '14 at 10:56
  • @BrianHooper But surely a jug is a large container from which you pour out water, milk, beer etc. into smaller glasses or cups. In the US they'd be called pitchers. Googled: Beer mugs are the more appropriate definitions google.com/…
    – Mari-Lou A
    Feb 23 '14 at 11:08
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    I've never thought of mugs being possibly made of glass. Very confusing!
    – Mari-Lou A
    Feb 23 '14 at 11:12
  • @Mari-LouA, yes, they are sometimes called mugs, but see also here, although that article does also refer to conical glasses, which I have never heard of by that name; they are in fact sleevers; I suspect there is some regional terminology involved as well. Feb 23 '14 at 11:58

In my experience, those large blue and red plastic containers for liquid (ubiquitous at large outdoor parties, keggers, etc.) are called 'cups' - not glasses, and certainly not mugs. The shape is well outside the boundaries of Lubov's prototype cup. Perhaps in this case the flimsy and very un-glasslike nature of the plastic is more pertinent than the shape? When it contains beer it could be called a 'glass of beer' - function over form ;) or more often just 'a beer' but when empty it is a 'cup'.

On the other hand, a hard plastic container shaped like a glass, whether clear or opaque, tall or squat, is commonly called a 'glass' where I come from.

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